Tuesday, October 16, 2007

The following table lists the probabilities that the home team would win each game given the rushing averages, passing averages (includes sack yards lost and sacks as pass attempts), sack rates, third down conversion rates, penalty yards, and interception and fumble rates (by number of completions and rushing plays) for both teams. A logistic regression model trained on 1996-2006 data computes the probabilities. The final score margin is Home team points - Away team points. The sum of these probabilities of victory form the expected win totals in the second table to be added after the Monday night game. The first table will be updated as more box scores come in.

Cleaning up from last week, where clearly I was not on the ball, I had to re-update the week 5 article with the P(win) for DAL@BUF, where the probability of Buffalo winning given their stats was 46.9886% despite the 6 turnovers Dallas coughed up. Without further ado, here are the week 6 numbers.

Home Team

Away Team

P(Home Team Won) (%)

Final Score Margin

BAL

STL

94.3709

19

CLE

MIA

98.4146

10

SD

OAK

99.5553

14

GB

WAS

22.3186

3

JAX

HOU

96.8639

20

KC

CIN

89.2048

7

CHI

MIN

28.3672

-3

NYJ

PHI

9.5042

-7

TB

TEN

87.7218

3

ARI

CAR

0.2296

-15

DAL

NE

25.6264

-21

SEA

NO

55.3389

-11

ATL

NYG

54.1972

-21

Teams that "should have" won but didn'tWashington Redskins (@ Packers), Win Prob = 77.6814% Favre threw 2 interceptions; Campbell threw only one. Favre averaged 4.33 yards a pass; Campbell averaged 5.25 yards. Green Bay was lucky enough to recover all four of their fumbles, while Washington recovered all of theirs. Washington really did outplay Green Bay, but they seem to have lost it on a couple of unlucky bounces.

Seattle Seahawks (vs. Saints), Win Prob = 55.3389% I was at the game, and I can tell you the Seahawks were never in it. Holmgren essentially forfeited the game when he decided to punt down 3 scores with 11 minutes left in the game. Hmm, think you'll need to score there sometime, Bubba? That said, this might reflect garbage time stats. Seattle managed 4.4 yards per carry, while the Saints gained only 3.7. Shaun Alexander was getting booed because he was slow and couldn't find holes. Leonard Weaver, the FB taking over for Mack Strong, is inflating this average (3 for 40) as is Hasselbeck's scramble. The Saints had 5 rushes (4 by Brees, 1 by Karney) of 0 yards to deflate their average. Seattle also managed to gain 6.9375 yards per pass versus 6.833 for the Saints. On the other hand, the Seahawks allowed sacks on over 10% of their pass plays. The Saints O-line pulled it together and gave Brees all the time in the world. The reason this game is in the Seahawks favor is probably the Saints' 2 fumbles, only one of which was actually lost. Remember, going by the FO philosophy of fumble recovery being random, I count all fumbles. In the end, however, take out the botched punt and give the Seahawks that blocked field goal, and it probably would have been 21-13 at the half and a very different game, considering that the Seahawks shut out the Saints in the second half. Yes, the Saints were likely trying to run out the clock, but there were a couple drives where the Hawks D prevented a couple of what would have been surefire scores.

So what does this mean? Except for Hail Mary passes, I don't remove any garbage time data from the system, so maybe this means that the system is wrong. On the other hand, if the stats were so close before garbage time that some ultimately meaningless drives led by Hasselbeck could tip the stats in the Seahawks' favor, maybe the game was closer than everyone thinks. Again, despite the Saints' great pass protection, which had been a problem in their first four games, that game could have easily been 21-13 at halftime. And remember, the Saints' offense had only one productive quarter. Nobody goes 0-16, and the Saints finally got some luck bouncing their way. Why the hell can't the Dolphins get some of that?!

Atlanta Falcons (vs. Giants), Win Prob = 54.1972% Manning threw two picks, and I threw out Harrington's Hail Mary interception at the end of the first half. Manning was also probably a little lucky that the picks he threw were around midfield rather than backed up in his own territory. Otherwise, it looks like the Giants did outplay the Falcons.

4 comments:

Jordan
said...

Probably a headache and a half to keep track of, but stats should be weighted differently depending on the score of the game. Like a 10 or 14 point differential cutoff line. Stats accumulated while the game is still close are more effective representations of a teams ability.

The model really dislikes teams that are ranked 30th, 26th, 26th and 26th in yards per attempt on rush off., rush def., pass off., and pass def. respectively. The Dolphins are 8th and 19th on rush off and pass off respectively. Yes, I'm a Dolphins fan, but the stats show they're not even the worst team in that division. They're not the 0-6 team people, including many Dolfans, think they are.

And I would expect some regression in accuracy. I've found accuracy to be highly dependent on home field advantage (which is really large for interconference games and nonexistent in divisional games this season so far).

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About the Author

My degree is in computer science, and the football research started as an independent study in artificial neural networks. As a lifelong NFL fan, I wanted to explore the relative importance of different factors in winning games. Since the research is still nascent, I wanted to put it out in the public domain and hopefully find others interested in teaming up. Once it becomes profitable, though... I just hope the mafia families running Vegas don't come to hurt me.